The present invention is related to Japanese patent applications No. 2000-169155, filed Jun. 6, 2000; and No. 2000-282258, filed Sep. 18, 2000, the contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to an air-mixing air-conditioning system, and more particularly, to an air-mixing air-conditioning system which controls the temperature of air blown into a vehicle interior after mixing the first air stream and the second air stream which differ in temperature.
2. Description of Related Art
In the air-mixing air-conditioning system of for example the invention disclosed in JP-A No. Hei 4-95520, an air stratum where the heated air flows (heated air stratum) and an air stratum where the cooled air flows (cooled air stratum) are alternately produced at an air mixing chamber to thereby insure proper mixture of the heated and cooled air streams.
The inventors examined this invention, finding that the heated and cooled air cannot be fully mixed in small volume air mixing chambers (air-conditioner casing) (particularly the length parallel with the direction of air flow).
In view of the above-described disadvantage, it is an object of this invention to provide an air-conditioning system capable of properly mixing the heated air and the cooled air even when the volume of the air mixing chamber (air-conditioner casing) (particularly the length parallel with the direction of air flow) is small.
To attain the above object, the air-conditioning system according to this invention is an air-mixing air-conditioning system capable of controlling the temperature of the air blown into the vehicle interior by mixing the first air stream and the second air stream which differ in temperature. The air-conditioning system has an air mixing chamber having a first air inlet opening at which the first air stream enters, a second air inlet opening which opens in a direction intersecting the first air inlet opening to take in the second air stream, and an air outlet opening 103 at which the first air stream entering at the first inlet and the second air stream entering at the second inlet flow out. Guide walls are provided that divide the first and second air inlet openings 101 and 102 into a plurality of ports and extend in a direction parallel to the air flow. The air mixing chamber is so constructed that at least one of the first and second air streams hits against the inner wall of the air mixing chamber 10 and then flows, after changing its direction of flow, to the air outlet opening. The guide walls are formed so that, as viewed from the air outlet opening, the air stratum of the first air stream and the air stratum of the second air stream are generated alternately. Furthermore, of the guide walls, the guide wall which guides the hitting air stream hitting the inner wall of the air mixing chamber is characterized in that its guide length a1 is 0.05 times or more and 0.5 times or less than the size L1.
The guide walls are provided to alternately produce the cooled air stream and the heated air stream as viewed from the air outlet opening 103 side. This construction improves the performance of mixing both air streams by increasing the contact surface area of the first and second air streams.
To reliably improve the air mixing performance, therefore, it is necessary to allow the flow of the first and second air streams into the air mixing chamber 10 with the two kinds of air strata reliably formed.
If in this case the guide length a1 and a2 of the guide walls is small, the first and second air streams go into the air mixing chamber without an air stratum formed, failing in the improvement in the air mixing performance.
Contrarily, if the guide lengths a1 and a2 of the guide walls are excessively large, the volume of the space (particularly the length parallel with the direction of air flow) in the air mixing chamber for mixing the air streams will decrease, resulting in insufficient mixture of the first and second air streams.
The air mixing performance can be improved as described later by setting the guide length a1 of the guide wall 104 which guides the hitting air stream like this invention.
Furthermore, the guide wall guides the non-hitting air stream of the first and second air streams flowing toward the air outlet opening side without hitting against the inside wall of the air mixing chamber. In another aspect, the air mixing performance can be further improved by setting the guide length a2 of this guide wall to 0.05 times or more and 0.5 times or less than the size L2 of a portion of the hitting air stream guide wall which is parallel to the direction of flow of the non-hitting air stream.
When the hitting air stream is flowing at a high velocity, the air temperature varies largely as described later. However, the temperature variation can be decreased by dividing the air inlet 104 guiding the hitting air stream so that the hitting air stream will flow at a specific velocity or at a lower velocity.
Furthermore, in another aspect of this invention, the temperature variation can be further decreased by a means for reducing the velocity of air stream positioned in at least one of the air inlets.
In another aspect, the angle of intersection xcex8 between the first air stream and the first air inlet opening is set at 80 degrees or more and 170 degrees or less. By thus setting the angle of intersection xcex8, it is possible to improve the air mixing performance.
In another aspect, the angle of intersection xcex3 between the direction of the main stream of air flowing out at the air outlet opening and the direction of the main stream of the first or second air stream is set at xe2x88x9240 degrees or more and 40 degrees or less.
It is therefore possible to improve the air mixing performance by thus setting the angle of intersection xcex3.
It is desirable to construct the air-conditioning system so that when the temperature of the first air stream is lower than the second air stream, and the air is blown downward in the vehicle interior, the angle of intersection between the direction of the main stream of outflow air and the direction of the main stream of the second air stream will be smaller than the angle of intersection between the main stream of the outflow air and the main stream of the first air stream.
Furthermore, it is desirable to construct the air-conditioning system so that when the temperature of the first air stream is lower than that of the second air stream and when the air is blown out upward in the vehicle interior, the angle of intersection between the direction of the main stream of the outflow air and the direction of the main stream of the first air stream will be smaller than the angle of intersection between the direction of the main stream of the outflow air and the direction of the main stream of the second air stream.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.